package com.ljd.server.config;

import com.ljd.server.config.security.JwtTokenUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.simp.config.ChannelRegistration;
import org.springframework.messaging.simp.config.MessageBrokerRegistry;
import org.springframework.messaging.simp.stomp.StompCommand;
import org.springframework.messaging.simp.stomp.StompHeaderAccessor;
import org.springframework.messaging.support.ChannelInterceptor;
import org.springframework.messaging.support.MessageHeaderAccessor;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.util.StringUtils;
import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer;

/**
 * WebSocket配置类
 *
 * @author ljd on 2022/2/7
 * @PACKAGE_NAME: com.ljd.server.config
 * @PROJECT_NAME: yeb
 */
@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {


    @Value("${jwt.tokenHeader}")
    private String tokenHeader;

    @Autowired
    private JwtTokenUtil jwtTokenUtil;
    @Autowired
    private UserDetailsService userDetailsService;

    /**
     * 添加这个Endpoint,这样在网页中就可以通过websocket连接上服务
     * 也就是配置websocket的服务地址,并且可以指定是否使用socketJS
     * @param registry
     */
    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        /**
         * 1. 将ws/ep路径注册为stomp的端点,用户连接上了这个端点就可以进行websocket通讯,支持前端使用socketJS进行连接
         * 2. setAllowedOrigins: 运行跨域
         */
        registry.addEndpoint("/ws/ep").setAllowedOrigins("*").withSockJS();
    }

    /**
     * 输入通道参数配置
     * @param registration
     */
    @Override
    public void configureClientInboundChannel(ChannelRegistration registration) {
        // 添加拦截器
        registration.interceptors(new ChannelInterceptor() {
            @Override
            public Message<?> preSend(Message<?> message, MessageChannel channel) {
                StompHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, StompHeaderAccessor.class);

                // 判断是否是连接,如果是,获取token,并设置到用户对象
                if(StompCommand.CONNECT.equals(accessor.getCommand())) {
                    String token = accessor.getFirstNativeHeader("Auth-Token");
                    if(!StringUtils.isEmpty(token)) {
                        String authToken = token.substring(tokenHeader.length());
                        String username = jwtTokenUtil.getUsernameFromToken(authToken);
                        // 如果用户名不为空
                        if(!StringUtils.isEmpty(username)) {
                            // 登录
                            UserDetails userDetails = userDetailsService.loadUserByUsername(username);
                            // 验证token是否有效
                            if(jwtTokenUtil.validateToken(authToken,userDetails)) {
                                UsernamePasswordAuthenticationToken authenticationToken =
                                        new UsernamePasswordAuthenticationToken(
                                                userDetails,
                                                null,
                                                userDetails.getAuthorities());
                                SecurityContextHolder.getContext().setAuthentication(authenticationToken);
                                accessor.setUser(authenticationToken);
                            }
                        }
                    }
                }
                return message;
            }
        });
    }

    /**
     * 配置消息代理
     * @param registry
     */
    @Override
    public void configureMessageBroker(MessageBrokerRegistry registry) {
        // 配置代理域,可以配置多个,配置代理目的地前缀为/queue,可以在配置域上向客户端推送消息
        registry.enableSimpleBroker("/queue");
    }
}
